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Practice Makes Perfect

factorial

All right! Now we’re cooking. Let’s try a factorial problem.

To calculate the factorial of a non-negative integer `x`

, just multiply all the integers from 1 through `x`

. For example:

`factorial(4)`

would equal`4 * 3 * 2 * 1`

, which is 24.`factorial(1)`

would equal`1`

.`factorial(3)`

would equal`3 * 2 * 1`

, which is 6.

### Instructions

**1.**

Define a function `factorial`

that takes an integer `x`

as input.

Calculate and return the factorial of that number.